Extinguishing device for electrical arcs comprising parallel insulating plates



3,235,693 MPRISING A. LATOUR Feb. 15, 1966 EXTINGUISHING DEVICE FOR ELECTRICAL ARCS CO PARALLEL INSULATING PLATES Filed July 3. 1961 lnvenfor l Andre Lafour bf /f//m United States Patent EXTINGUISHING DEVICE FR ELECTRHCAL ARCS COMPRISING PARALLEL INSULATING PLATES Andr Latour, 18 Ave. Felix-Viallet, Grenoble, France Filed `luly 3, 1961, Ser. No. 121,433 Claims priority, application France, July 1, 1960, 4,266 9 Claims. (Cl. Z00-144) This invention relates to extinguishing devices for electrical arcs drawn between separable contact members located in an arc formation chamber of an electrical circuit breaker, and more particularly to extinguishing devices of this type having an arc extinguishing chamber which comprises a set of at least two parallel plates of insulating material spaced apart from one another and disposed transversely of the direction of separation of the contacts or the initial direction of the arc.

The spaced parallel plates of insulating material define narrow arc separating or extinguishing chambers and are provided with conductive members which are generally V or U-shaped and Whose legs or wings embrace or straddle the individual insulating plates. Conductive members of this general type and configuration are disclosed in my U.S. Patent No. 2,707,739. The web portion of the V or U-shaped conductive member straddles the side or edge of an insulating plate while the legs `or wings of the conductive member extend along the faces of the insulating plates in a substantially parallel arrangement. The opposed parallel win gs of each conductive member are slightly offset or divergng relative to each other. Conductive members or paths are thus provided on the faces of the insulating plates which attract and conduct the arc drawn between the insulating plates in such a manner as to turn the arc to form expanding curved or looped configurations within the narrow spaces between the insulating plates. The initial arc in contact with the conductive members is thus subdivided into a number of partial arcs which enter the extinguishing chambers where they are extended and developed into loops of substantially oblong form. The partial arcs are effectively cooled upon corning in contact with the adjacent parallel plates of insulating material and are thereby extinguished.

It has been found that in the case of large intensities which correspond to powerful circuit interrupting arcs, the conventional form and arrangement of insulating plates wherein each plate is in direct contact with the initial circuit interrupting arcs on its two faces is not very effective when a very substantial amount of heat is released.

It is therefore an object of the present invention to provide an improved arrangement wherein heat developed in the arc formation chamber is discharged through the insulating plates in a direction substantially perpendicular to the axial direction of the plates.

It is a further object of this invention to provide an improved arrangement whereby the heat developed in the arc formation chamber is discharged in a direction parallel to the axial direction of the insulating plates.

According to the invention openings or flues are provided in the insulating plates making thus possible a circulation of air. This may be obtained by means of two insulating plates disposed so as to leave a space or interval therebetween.

According to an additional feature of the invention vertical ribs are provided on the surface of the insulating plates in proximity to each other so as to produce grooves which increase the effective cooling area of the surface of the insulating plates while simultaneously improving the air circulation between the plates in a vertical direction.

The arrangement according to the invention for obtaining a transverse circulation of air through the individual insulating plates may be combined advantageously by employing porous insulating plates which permit the passage of gases derived from the circuit interrupting operation in the deionized state through the pores of the plates and their discharge through the spaces between the plates arranged to provide a chimney or flue for the exhaust gases. Plates of this kind have been described in U.S. Patent No. 2,772,334 issued to A. Latour for Refractory Body for Electrical Apparatus.

The arrangement of vertical ribs producing intermediate grooves in close proximity to each other improves the effectiveness of the arc extinguishing device so that the conventional flame arrestors may be eliminated completely or partly.

The arrangement of the vertical ribs defining gas discharge channels provides a laminar space in which the arc may be extinguished wherein according to the invention such a space is provided between the ribs of two adjacent plates which are directed with their ribs confronting each other. This results for the same plate depth in a much more substantial interval between the surfaces of adjacent plates at the level of the conductive members which makes it possible to locate conductive members of much greater thickness on the insulating plates. This possibility of increasing the thickness of the conductive members is very important in the case of large current intensities.

In order to increase the transverse discharge of circuit interrupting gases the ribs which extend along the periphery of the plates are provided with a number of bosses or raised portions so that the ribs are not in contact with the adjacent plates over the entire peripheral extent and thus leave an interstice or slit. However, the lateral escape of the flames is avoided by means of suitable sealing members. This arrangement is also appropriate for arc extinguishing devices in which the ribbed faces of all the plates are oriented in the same direction, or more than two consecutive insulating plates may be arranged in a set wherein each plate is provided with spacing ribs on each of its faces.

These and other objects and features of the invention will become apparent upon reading the specific description of the invention in connection wtih the accompanying drawing which forms part of the specification and which illustrates by way of example only an embodiment of the invention. In the drawings:

FIG. l shows a front view in elevation of a stack of three insulating plates which are arranged according to the invention and which constitute a sub-assembly of arc extinguishing devices according to the invention.

FIG. 2 shows a cross-section along line 2 2 of FIG. l.

Referring now particularly to the drawing, reference numerals l, la and llb `designate respectively three identical insulating plates each provided with a peripheral flange or rib 2 having a groove 3 in which a suitable seal 3a is disposed. Each of the three insulating plates is provided on one of its faces with a plurality of vertical ribs 4 which define discharge grooves or channels for the hot gases generated during the circuit breaking interruption. The channels 4a are preferably distributed over the entire useful extent of the insulating plate. Flame arrestors 5, of very small size compared to the conventional llame arrestors, are disposed at the top of the gas discharge channels. The conductive members 6 straddle in this arrangement two insulating plates la and 1b disposed back to back.

Assuming that insulating plates of the same depth are employed as -in the conventional arrangement, there is available therefore in the arrangement according to this invention in reference to the prior art arrangement an; increased space for locating the wings of the conductive members 6. According to the invention reinforcing members 7 are thus connected to the Wings of conductive members 6. The reinforcing members may be a part of the wings or may be connected thereto by any suitable means and if desired may be lmounted thereon with a suitable interval. A slit or interstice 8 is provided between two plates mounted back to back due to spacer bosses 9. The plates may be connected together at 10.

A discharge of exhaust gases and of heat may be obtained from the arc extinguishing faces by facilitating `the discharge `of the gases along the periphery of the plates in a manner known per se.

For this purpose raised portions which constitute spacer `blocks or bosses may be disposed on the peripheral ribs 2 so that these ribs are no longer in contact with the opposite ribs along the entire length but leave a slit or interstice therebetween. In a suitable manner porous seals may be disposed between two adjacent plates so that the plates are still interconnected sufficiently to prevent the escape of flames from the extinguishing chambers.

What is claimed is:

1. In a device for extinguishing an electric arc drawn between separable contact members and comprising a plurality of porous insulating plates disposed in closely spaced relation transversely of the direction of separation of said contact members and forming arc extinction spaces therebetween, conductive means mounted on the lower part of said Iplates for splitting up said arc into arc sections which bridge the spaces between pairs of adjacent conductive means, said conductive means extending into said arc extinction spaces to a predetermined upper level for drawing said are sections into said arc extinction spaces and causing them to form peripherally expanding loops, said porous plates defining substantially parallel wall means enclosing cooling interstices providing discharge passages of the gases generated by said arc sections in said arc extinction spaces through said plates, said interstices extending upwards between successive arc extinction spaces at least from the vicinity of said upper level, said conductive means straddling the lower edges of said wall means to confine said arc sect-ions to said arc extinction spaces.

2. A device as described in claim ll, including a plurality lof ribs on said plates in said arc extinction spaces and extending upwards at least from the vicinity of said upper level, said ribs defining a plurality of grooves providing discharge channels for the gases generated by said arc sections.

3. A device as described in claim 2, wherein said plates have two parallel faces, one face being substantially .plane the opposite face comprising said ribs, said plane faces being constituted by said wall means, said opposite faces of adjacent plates being disposed in confronting relationship.

4. A dev-ice as described in claim 3, wherein said conductive means comprise wings extending into said arc extinction spaces, said wings being of a thickness which is substantially equal to the thickness of the ribs of two confronting faces of said plates,

5. In a device for extinguishing an electric arc drawn between separable contact members and comprising a plurality of insulating plates disposed in closely spaced relation transversely of the direction of separation of sai-d contact mem'bers so as to define wall means enclosing a corresponding plurality of arc extinction spaces, conductive means ymounted on the lower part of said plates for splitting up said arc into arc sections which bridge the spaces 4between pairs of adjacent conductive means, said conductive means comprising wings extending into said arc extinction spaces for drawing said arc sections into said arc extinction spaces and causing them to form expanding loops, said wall means having closely spaced ribs projecting therefrom for providing cooling grooves, said grooves extending from said wings over the entire part of said wall means disposed in heat transfer relation to said arc sections, the height of said ribs being at most equal to the spacing between said wall means.

6. In a device for extinguishing an electric arc drawn between separable contact members and comprising a plurality of insulating plates disposed in closely spaced relation transversely of the direction of separation of said contact members and forming arc extinction spaces therebetween, -conductive means mounted on the lower part of said plates for splitting up said are int-o arc sections which bridge the spaces -between pairs of adjacent conductive means, said conductive lmeans extending into said arc extinction spaces to a predetermined upper level for drawing said arc sections into said arc extinction spaces and causing them to form peripherally expanding loops, said plates having sides facing said arc extinction spaces and corrugated at least from the vicinity of said upper level upwards, said corrugations dening a plurality of parallel grooves providing discharge channels for the gases generated by said arc sections, said grooves being disposed so that the spacing between said sides is variable in a direction perpendicular to the longitudinal direction of said corrugations.

7. ln a device for extinguishing an electric arc drawn between separable contact members and comprising a plurality of insulating plates disposed in closely spaced relation transversely of the direction of separation of said contact members and forming arc extinction spaces therebetween, conductive means mounted on the lower part of said plates for splitting up said arc into arc sections which `bridge the spaces between pairs of adjacent conductive means, said conductive means extending into said arc extinction spaces to a predetermined upper level for drawing said arc sections into said arc extinction spaces `and causing them to form peripherally expanding loops, the sides of both plates facing each arc extinction space having ribs projecting therefrom extending along the plates at least from the vicinity of said upper level upwards, said ribs defining a plurality of cooling grooves, the height and the width of said r-ibs and said grooves |being at most equal to half the spacing between said sides.

8. In a device for extinguishing an electric arc drawn between separable Contact mem-bers and comprising a plurality of sets of two porous insulating plates mounted in closely spaced relation transversely of the direction of separation of said Contact members, each set of two plates having two confronting sides and intermediate means for spacing lsaid two sides from each other to provide arc extinction space therebetween, conductive means mounted on the lower part of said plates for splitting up said arc into arc sections which bridge the spaces between pairs of adjacent conductive means, said conductive means extending into said arc extinction spaces to a predetermined upper level for drawing said arc sections into said arc extinction spaces and causing them to form peripherally expanding loops, said porous plates defining substantially parallel wall means enclosing cooling interstices providing discharge passages of the gases generated by said arc sections in said arc extinction spaces through said plates, said interstices extending upwards between ysuccessive arc extinction spaces at least from the vicinity of said upper level, said conductive -rneans straddling the lower edges of said wall means to confine said arc sections to said arc extinction spaces.

9. A device according to claim 8 wherein said confronting sides of each set of two plates have vertically ribbed surface-s extending from the vicinity of said conductive means upwardly and the sides of said plates between two adjacent sets providing said interstices have plane surfaces.

(References on following page) 5 6 References Cited by the Examiner 2,868,927 1/ 1959 Wood 200-144 UNITED STATES PATENTS 2,888,539 5/1959 LatOllI 20'0--147 11/ 1937 Hammerly ZOO-144 FOREIGN PATENTS 12/ 1942 Boehne 200-144 10/1953 Salers 200 144 5 715,121 9/1954 Great Brltam.

5/ 1955 Phillips et a1 200-144 E Y 6/1956 Latour n 20o-144 KATHLE N H. CLAFF Puma; y Exammer.

8/1958 Pfeer et aL 200 147 MAX L. LEVY, ROBERT K. SCHAEFER, Examiners. 

1. IN A DEVICE FOR EXTINGUISHING AN ELECTRIC ARC DRAWN BETWEEN SEPARABLE CONTACT MEMBERS AND COMPRISING A PLURALITY OF POROUS INSULATING PLATED DISPOSED IN CLOSELY SPACED RELATION TRANSVERSELY OF THE DIRECTION OF SEPARATION OF SAID CONTACT MEMBERS AND FORMING ARC EXTINCTION SPACES THEREBETWEEN, CONDUCTIVE MEANS MOUNTED ON THE LOWER PART OF SAID PLATES FOR SPLITTING UP SAID ARC INTO ARC SECTIONS WHICH BRIDGE THE SPACES BETWEEN PAIRS OF ADJACENT CONDUCTIVE MEANS, SAID CONDUCTIVE MEANS EXTENDING INTO SAID ARC EXTINCTION SPACES TO A PREDETERMINED UPPER LEVEL FOR DRAWING SAID ARC SECTIONS INTO SAID ARC EXTINCTION SPACES AND CAUSING THEM TO FORM PERIPHERY EXPANDING LOOPS, SAID POROUS PLATES DEFINING SUBSTANTIALLY PARALLEL WALL MEANS ENCLOSING COOLING INTERSTICES PROVIDING DISCHARGE PASSAGES OF THE GASES GENERATED BY SAID ARC SECTIONS IN SAID ARC EXTINCTION SPACED THROUGH SAID PLATES, SAID INTERSTICES EXTENDING UPWARDS BETWEEN SUCCESSIVE ARC EXTINCTION SPACES AT LEAST FROM THE VINCINITY OF SAID UPPER LEVEL, SAID CONDUCTIVE MEANS STRADDING THE LOWER EDGES OF SAID WALL MEANS TO CONFINE SAID ARC SECTIONS TO SAID ARC EXTINCTION SPACES. 